Residents in the southern Philippines are making hasty preparations ahead of an approaching tropical storm.

Sanba, known locally as Basyang, is expected to make landfall on the country's second largest island, Mindanao, at approximately 00:00 GMT on Tuesday.

Although it is not expected to be a particularly intense storm in terms of the wind, the amount of rain is a major concern.

Some 200 to 300 millimetres of rain is expected to pour down on Mindanao, which is home to 20 million people and one that does not usually fair well from the impact of tropical storms.

Its vulnerability is partially due to the recent explosion in the population that has led to major changes to the island's environment and infrastructure.

The natural forests which coated the hillsides have been felled and rustic huts have been hastily constructed.

The lack of vegetation means that there is nothing to bind the soil to the hillside, making it prone to landslides. Meanwhile, the rustic huts provide little protection against landslides.

The vulnerability of Mindanao is also because, historically, it is rarely hit by tropical storms. The island is within six to nine degrees north of the equator, which is too close to generate the "spin" in the atmosphere needed to produce these cyclones.

Usually, the islands are only hit once every 12 years, but climate change has ensured that the storms have become more frequent, and each time they bring deadly consequences.

The last storm to hit Mindanao was in December 2017. Tropical Storm Tembin, known locally as Vinta, brought torrential rain which triggered landslides and flooding which killed at least 200 people.

Mindanao was also hit in 2011. The flooding and landslides from Tropical Storm Washi (Sendong) killed a staggering 1,249 people.

Neither Tembin nor Washi were particularly intense storms as far as the winds were concerned. In both instances, it was the rain which triggered the disaster.

The local authorities are hoping to avoid a similar disaster from Tropical Storm Sanba.